Polymethine dye intermediates



Patented Jan. ,1942 A i g I UNITED STATES. PATENT OFFICE azsazs POLYMETHINE DYE INTERMEDIATES Robert a. some, Rochester, N. r., ti e to Eastman Kodak Company, Rochester, N. I, a corporation of New Jersey No Drawing. Application October 18, 1940, Serial No. 361,765

1': Claims. (01. zoo-:04)

This invention relates to polymethine dye indlflerent kinds. My new intermediates are more termediates and to a process for preparing them. soluble in most solvents than the acetanilido A kind of polymethine dye intermediate of compounds. considerable value is that obtained by condensing It is. therefore, an object of my invention to the condensation product of a B-alkoxyacrolein 5 provide new dye intermediates and a process for acetal and a primary aromatic amine, with a preparing them. A further object is to provide cyclammonium quaternary salt containing a rea process for preparing polymethine dyes. Other active methyl group, in the presence of acetic objects will appear hereinafter.

anhydride. The formation of such a dye inter- In accordance with my invention, I condense mediate can be illustrated as follows: 10 a p-alkoxyacrolein acetal with a cyclammonium H01 quaternary salt containing a methyl group in the 1) C2H5OCH=CHCH(OCiHE)i+ IHIN I I alpha position. employing as a reaction medium,

substantially anhydrous acetic acid, such as cmcoho CCH:+CtHs-NH-CH=CHCH=NCnH|.HCi

CzHs I s 2CCH=CK-CH=CH- +cmcoon+nci+camzm 3 CIHI emf I 2-(4-acetanilido-L3-butadienyhbensothiazole ethiodide Dye intermediates, such as 2-(4-acetanilido-L3- glacial acetic acid. The process can be illusbutadienyl) -benzothiazole ethiodide, can be contrated for the benzothiazole series as follows:

densed, in the presence of a basic condensing 8 agent, with some cyclammonium quaternary salts CECOOH containing a reactive methyl group, to give .di- 5 C-CHl'i' l i l i)l -v carbocyanine dyes, and with some organic compounds containing a ketomethylene group, likewise in the presence of a basic condensing agent, to give merodicarbocyanine dyes. s

I have now found that dye intermediates which 40 1 1 can be condensed with cyclammonium quater- =3 nary salts and with ketomethylene compounds to give dicarbocyanine dyes and merodicarbocy- N anine dyes, can be prepared by direct condensa-e f tion of a p-alkoxyacrolein acetal with a cyclam- 45 momum quaternary salt. containing a th l 2-(4-ethoxy-i,3-butadienyl)-benzothiasolc ethiodidc group in the alpha position. Thus, I have been My process is not tobe confused with a proable to arrive at useful dye intermediates from posal, given in the prior art, to prepare dicarp-alkoxyacrolein acetals, without going through bocyanine dyes by condensing p-alkoxyacrolein the p-anilinoacrolein anil stage. My new interacetals with cyclammonium quaternary salts conmediates contain an alkoxy 1,3-butadienyl group taining a reactive methyl group, employing a reinstead of an acetanilido-1,3-butadienyl group, action medium of acetic anhydride. I have found and can be condensed, I have found, with many that with acetic anhydride no trace of dye insubstances more readily than can the acetanilido termediate can be isolated, but only symmetrical compounds, to give polymethine dyes of several dicarbocyanine dye, even in the presence of a large excess of the p-alkoxyacrolein acetal.

In carrying out my new process. an excess of ,--l-alkoxyacrolein acetal is advantageously employed, from one and one-half to three molecular proportions of acrolein acetal for each molecular EXAMPLE 1.-2- (4-ethoxy-1,3-butadienyl) benzothiazole ethiodide can; I

30.5 g. (1 mol.) of 2-methylbenzothiazole ethiodide and 34.8 g. (1 mol.+l% excess) of p-ethoxyacrolein diethyl acetal were mixed together in 100 cc. of glacial acetic acid. The mixture was heated for ten minutes on a steam bath, with stirring. The green reaction mixture was chilled to 0 C., the dye intermediate filtered ofi, washed with acetone and then with water and finally dried in the air. zation from absolute ethyl alcohol (30 cc. per gram of intermediate, the dye intermediate was obtained as bright green crystals, melting with decomposition at 177 to 178 C. Yield 18.8 g. (49%).

EXAMPLE 2.-2- (3-ethoxy-L3-butadienyl) benzozazole ethiodide 28.9 g. (1 mol.) of 2-methylbenzoxazole ethiodide and 26.1 g. (1 mol.+50% excess) ofp-ethoxyacrolein diethyl acetal were placed in 60 cc. of glacial acetic acid. The mixture was heated for ten minutes on a steam bath, with stirring. The green reaction mixture was chilled with an ice bath, the chilled mixture diluted with 300 cc. of diethyl ether, and the diluted mixture stirred until the intermediate crystallized out. The intermediate was filtered off, washed with diethyl ether and dried in the air. The dark blue crystals thus obtained were deliquescent. Yield 24 g. (65%).

EXAMPLE 3.-2- (4-ethoxy-L3-butadienyl) p-naphthothiazole ethiodide V CzHs 35.5 g. (1 mol.) of 2-methyl- 3-naphthothiazole ethiodide and 34.8 g. (1 mol.+l00% excess) of p-ethoxyacrolein diethyl acetal were placed in 100 cc. of glacial acetic acid. The mixture was heated forfive minutes on a steam bath, with stirring, The brown reaction mixture was chilled to 0 C. and the intermediate filtered off. It was washed with acetone and water, and finally dried in the air. After recrystallization from methyl alcohol (20 cc. per gram of inter- After recrystalli- Exnnu 4.2-(d-ethnxy-lj-butadienyl) a-MPhthOMZOlC ethiodide 17.0 g. (1 mol.) of Z-methyI-a-naphthoxazole ethiodide and 17.4 g. (1 mol.+l00% excess) of fl-ethoxyacrolein diethyl acetal were placed in 50cc. of glacial acetic acid. The mixture was boiled, under reflux, for one minute. The green reaction mixture was cooled, diluted with 300 cc. of diethyl ether and chilled. The ether layer was decanted. The residue was stirred with 50 cc. of hot acetone, until the intermediate became crystalline. The acetone mixture was then chilled and the intermediate filtered 01!. It was washed with acetone and dried in the air. 9.8 g. (47% yield) of green crystals, melting at 170 to 171! C. with decomposition were thus obtained.

Exnnu: 5.Z-(4-ethoxv-L3-butadienyl) p-naphthoxazole ethiodide 17.0 g. (1 mol.) of Z-methyl-fl-naphthoxazole ethiodide and 17.4 g. (1 mol.+l00% excess) of p-ethoxyacrolein diethyl acetal were placed in 50 cc. of glacial acetic acid. The mixture was boiled, under reflux, for live minutes. The brown reaction mixture was chilled, diluted with 300 cc. of diethyl ether. The diluted mixture was chilled, and stirred, and the ether layer then decanted. The residuewas stirred with 50 cc.

' of hot acetone, until the intermediate became 29.9 g. (1 mol.) of quinaldine ethiodide and 34.8 g. (1 mol.+l00% excess) of p-ethoxyacrolein diethyl acetal were mixed together in cc. of glacial acetic acid. The mixture was boiled, under reflux, for five minutes. The brown reaction mixture was cooled, diluted with 500 cc. of diethyl ether, and the diluted mixture was allowed to stand for four hours at 0 C. The ether layer was then decanted through a filter, and the residue was stirred with 50 cc. of acetone, until the intermediate became crystalline. The intermediate was then filtered ofi with suction, washed with acetone and dried in the air. 24.0 g. (63% yield) oi greenish brown crystals were thus obtained. A pJrtion of the crystals were recrystallized from methyl alcohol (10 cc. per gram of intermediate) and found to melt at 182 to 184 C. with decomposition.

EXAMPLE '7.2- (ethozy-LS-butadienyl) benzoselenazole ethiodide 35.2 g. (1 mol.) of 2-methylbenzoselenazole ethiodide and 34.8 g. (1 mol.+'100% excess) of ,l-ethoxyacrolein diethyl acetal were mixed to- 5 odide and 69.6 g. (1 mol.+100% excess) 01' pethoxyacrolein diethyl acetal were mixed together in 100 cc. of glacial acetic acid. The mixture was heated for ten minutes on a steam bath, with stirring. The brownish reaction mixture was cooled, diluted with 300 cc. of diethyl ether, and then chilled to 0 C. The ether layer was decanted and the residue stirred with acetone, until the intermediate was crystalline. The acetone mixture was chilled and the intermediate filtered oil. It was washed with acetone and dried in vacuo over anhydrous potassium carbonate. In this manner were obtained 15.9 g. (24% yield) of hygroscopic brown crystals, melting at 124 to 127 C. with decomposition.

In a manner similar to that illustrated in the foregoing examples, 2- (4-ethoxy-l,3-butadienyl) benzothiazole pheniodide can be prepared from Z-methylbenzothiazole pheniodide, and 2-(4- ethoxy-1,3-butadieny1) 3,4 trimethylenebenzothiazolium iodide can be prepared from 2-methyl- 3,4-trimethylenebenzothiazolium iodide.

2-Methylbenzothiazole pheniodide and 2- methyl-3,4-trimethylenebenzothiazolium iodide can be prepared as described in the copending application of Leslie G. S. Brooker and Homer W. J. Cressman, Serial No. 353,502, filed August 21, 1940, by oxidizing thioacetyldiphenylamine or 1-thioacetyl-1,2,3,4 tetrahydroquinoline with iobenzothiazole ethiodide and 1.0 g. (1 mol.) oi 2- As demonstrated in the foregoing examples, the cyclammonium quaternary salts are advantageously employed as the quaternary iodides. However, any quaternary salt torm can be employed.

My newlntermediates can becondensed with cy'clammonium alkyl quaternary salts containing a methyl group in the alpha or gamma position, i. e. in one oi. the so-called reactive positions, in the presence or a basic condensing agent, to give symmetrical and unsymmetrical dicarbocyanine dyes. I have found that pyridine and trialkylamines dissolved in acetic anhydride are especially suitable basic condensing agents. The following examples illustrate the formation of dicarbocyanine dyes from my new'intermediates.

These examples are not intended to limit my invention.

EXAMPLE 9.-3,3-diethulthiadicarbocuanine iodide 1.3 g. (1 mol.) of 2'-(4-ethoxy-L3-butadienyl)- methylbenzothiazole ethiodide were mixed together in 15 cc. of pyridine. The mixture was boiled, under reflux, for five minutes. Green crystals of dye separated from the boiling mixture. The mixture was chilled to 0 C., the dye filtered off, washed with acetone and water, and finally dried in the air. It was recrystallized from methyl alcohol (160 (:0. per gram of dye) and obtained as bright green crystals, melting with decomposition at 251 to 253 C. Yield 1.3

EXAMPLE 10.1 ',3-diethyloxa-2'-dicarbocyanine iodide 1.86 g. (1 mol.) oi! 2-(4-ethoxy-1,3-butadienyl) benzoxazole ethiodide and 1.5 g. (1 mol.) of quinaldine ethiodide were mixed together in 15 cc. of acetic anhydride containing 0.5 g. (1 mol.) of triethylamine. The mixture was boiled, under reflux, for one minute. The blue solution was cooled, diluted with cc. of diethyl ether, the

diluted mixture chilled to 0 C. and the ether layer decanted. The residue was stirred with 10 cc. of methyl alcohol. The methyl alcoholic mixture was chilled, the dye filtered oiI, washed with methyl alcohol and dried in the air. After recrystallization from methyl alcohol (25 cc. per gram of dye), the dye was obtained as green crystals melting with decomposition at 149 to 150 C. Yield 1.1 g. (44%).

In addition, the following dicarbocyanine dyes dine for example.

were prepared:

Dye and yield (recrystallized) Alkoxy intermediate l,3-diethylthia-2-dicarbocyanine iodide U 7)- 1 l,3 di ethylthia -4' dicab bocyanine iodide 3,3'-d1etliy]-4,5-benzothladicarbocyanine iodide (39%).

3,3- diethyl-4,5,4',5 -dibenzothia-dicarbocyanine iodide (32%).

1,1 diethy] 2 2 dicarbocyanine io ide (65%).

3,3-diethyloxathiadicarbocyanine iodide (58%) 3,3 -diethyloxa-dicarbocyanine iodide (54%). l,3-diethyloxa-4'-dicar- 2-(4-ethoxy-1,3-butadienyD-benrothiazgle ethiodide.

bocyanine iodide (24%) Cyclammonium salt B i d C 1 d m containing methyl as 0 con ensmg 0 or an me ng group agent point, C. I

Quinaldine ethiodida. 'Irietliylamine Green crystals (golden and acetic anreflex) 234-236 d. hydride.

Lepidine ethiodide do Green crystals Z-methyl-fl-naphtho- Pyridine Dark green crystals thiazole ethiodide, 189-191 d.

2-methyl-fl-naphthodo Green crystals 225- tliiazole etho-p-tolu- 227 d.

- encsulionate.

Qninaldine ethiodide do Gigelnd needles 260- 2-methyl-benzothia- .do Green needles 242- zole ethiodide. 244 d.

2-metliyl-benzoxazole .d0 Blue crystals (silvery ethiodide. reflex) 229-230 (1.

Lepidine ethiodide Triethylamine Green crystals (golden and acetic enreflex) 132-134 d. hydride.

Oyclammonlum salt Dye and yield Bulc condeml Color and meltin unmanned, Alkoxy intermediate containing methyl "mt pom,

3,3'-dletllylselena-lllcar- 2-(4-ethoxy-l 3-buta- 2-methyl-benrolelena- Pyridine- Green needles 236- bocyauiue iodide(ll9%) (n w: mm lenasole ethiodide. m a.

10 e e e. 3,.'l-diethylselenathladldo z-methyl -benmthla- ..do. Green tale zloar biicy ne iodide sole ethiodide. 237 d.

a 3,3-d ethyloxazelenadi- .rlo 2-methyl-bensoxamle .....do Gr n egggcyanlne iodide etlilodide. rrlex% f a-ethyimethylthlaiht 2-(4-ethoxy-L3-butaz-methyl-benm-thl- ..dn Dull blue crystals 1e3- nzoiino dicarbocyandienyD-thiazolino 81-010 cthlodide. 166 d. nine iodide (26%). methiodlde.

My new intermediates can be condensed with heterocyclic organic compounds containing a ketomethylene group, in the presence of a basic condensing agent, to give merodicarbocyanine My new intermediates can be condensed with N-alkyl or N-arylpyrroles to give polymethine dyes which are useful as light-screening substances in the preparation of photographic eledyes. Thus, 2-(4-ethoxy-L3-butadienyl) -benments. Polymethine dyes obtained in this manzothiazole ethiodide was condensed with 3-ethyl 2o ner are bleachable by the ordinary alkaline rhodanine, in the presence 01 triethylamine and developers. The following examples will serve to acetic anhydrine to give 3- ethyl-5-[(3-ethyldemonstrate the manner of obtaining these 2(3) -benzothiazolylidene) butenylidenel-rhodapolymethine dyes. nine, in the form of blue needles melting at 234 to 236 0. with decomposition, after recrystalliz- Emma: 3 et ul Z benzothiazole) (1- ation from a mixture of pyridine volumes) tzl -u-dim t u dmv l tetfllmet ine and methyl alcohol volumes). The same inil e o de termediate was also condensed with 3-methyl- 1-phenyl-5-pyrazolone and with 1-ethyl-3- phenyl -2-thi0hydantoin. 3U 2C C H: C n H=C H My new intermediates can be condensed with I primary or secondary aliphatic or aromatic 2 6 4.0g, amines to give hemidicarbocyanine dyes. The A\ 1 following example illustrates the formation of I such dyes: 1 u EXAMPLE 11.2-(4-piperzdin0 1,3 butadienyl) (1 of y-L -butadienyl)- benzothiazole ethiodide benzothiazole ethiodide and 7.6 g. (1 mol.+100% -2 1.93 g. (1 mol.) of 2-(4-ethoxy-1,3-butadienyl) excess) 1 heptyl 5 dimethylpyrmle were m dd d 1 7 (1 1 300 mixed together in 50 cc. of acetic anhydride. 22:52:. sessile; 5.2;; mes were... mm was mm cc. of absolute ethyl alcohol. The mixture was minutes stirring Green crystals or the dye separated from the boiling reaction mixboiled, under reflux, for ten minutes. The ret Th u t to 0 action mixture was then chilled, 200 cc. of diethyl g 3 on mix was chilled ether added, and after again chilling, the ether 8 ye red washed with acetone and layer decanted through a filter. The acetone dried in the am After recrystallization from mixture was chilled, the dye filtered off, washed methyl alcohol (22 P E e-m 9 i the with acetone and water and finally dried. Yield dye was Obtained as green crystals. w th 8 bright of blue crystals 1.7 g. (81%). After several retalli reflex. and m ltin w h d o posi i n crystallizations from absolute ethyl alcohol, the at 233 to 234 C. with decomposition. The dye dye was obtained in small yield as pink crystals, gave a red solution in methyl alcohol. Yield melting with decomposition at 266 to 268 C. 8.0 8.

The same intermediate was condensed with In a similar manner, the following tetramethaniline, inecyanine iodides were obtained:

Dyc Intermediate Pyrrole Color and fuelling mi y l aifxipoint hol solution (3-ethy1-2-benzoxazole)(l- 2-(4-ethoxy-L3-butadil-heptyLZ-rdimethyl- Red crystals metai- Red.

heptyl)-2,5-dimethyl-3- eggil-ebenzoxazole ethipyrro e. be reflex 191-192.

8 (55531-2-benzoxazole)-(lv. do l-lauryl-2,5-dimethyl Red crystals 189-190. Red.

lauryl-2,5-dimethyl-3- pyrrole. (3 e ic gl-i-benzoxazole)-(lido l-ethyl-2,5-dimethyl- Green crystals 221- Red.

ethyl-)2,5-dimetbyl-3- pyrrole. m.

e (l c tg iaj-dimethyl-ii- .do l-cetyl-2,5-dimetbyl- Red crystals 189-193. Red.

pyrrole; (3 -ethyl-2-benzpyrrole. (l tigy l-zj-dimethyl-li- 2-(4-ethoxy-l,3-butal-ethyl-2,5-dimethyl- Violet crystals Red.

pyxrole)-(3-ethyl-2a-naphdienyl-aaphthoxazole pyrrole. 167. thoxazo1e)- ethiodide. (3-ethyl-2-a-naphthoxazole)- do i. l-lauryl-2,5-dimethyl- Green prism green Red.

(1 -laiiryl -2,5-dimethyl-3 pyrrole. reflex 198-199. (l t ii ylhfi-dimethyl-li- 2-(4-ethoxy-l,3-butal-ethyl-2,6-dimethyl- Red crystals silvery Red.

pyrrole)-(l-cthyl-2-fl-naphdienyD-B-naphthoxazole pyrrole. reflex 231-232. thoxazole)- ethiodide. (1-ethyl-2,5-dimethyl-3- 2-(4-ethoxy-l,3-buta- 1-ethyl-2,5-dimethyl- Green stalsgreen- Red.

lne(3m)-(l-etliyl-2-quingigryh-quinoline ethiopyrrole. ish re ex 238-239. 0

Oolorot Color and melting D e Intermediate Pyrrole methylalcoy ml solution (3-ethyl-2-benzothiuole)-(l- 2--(4-ethoxy-l,3-butal-ethyl-2,5-dimethyl- Greenneedlesbright Red.

.ethyl-mo-dimethylddienyD-bcnsothiuole pyrrole. green reflex 246- pyrrola)- etbiodlde. 247. (ii-ethyl-2-benz0thialolo)- .-...do l-pbenyl-2,6-dimethyl- Green crystals 247- Red. (2,5-dlmethyl-l-phenyl-3- pyn'ole. 249.

m g (l ethyl-2J-dimethyl'3- 2-(4-ethoxy-l S-butai-ethyl-2,5-dimethyl- Brown crystals 235- Orange.

pymle)-3-methyl-2-thim l)-thiuolinomethpyrrole. 23o. 81D 6- s O. (3-ethyl-2-benzosolenazole)- 3- 4-othoxy-l,8-butal-ethyI-ZS-dimethyl- Green needles 24l- Bluish-red.

(l-ethyl-2,5-dimethyl-3- lenyl),-benaoselenar.o pyrrole. 242. py ethlodi o.

My new intermediates can be represented by the following general formula:

N==CCH=CHCH=CH-OR' wherein R represents an organic radical selected from the group consisting of alkyl and aryl groups, R, represents analkyl group, X repre-. sents an acid radical, and Z represents the nonmetallic atoms necessary to complete a heterocyclic organic nucleus. Intermediates of the above formula wherein Z represents the nonmetallic atoms necessary to complete a quinoline, a benzoxazole, a. nap'hthoxazole, a benzothiazole, a naphthothiazole, a benzoselenazole or a thiazoline nucleus, are especially useful in the preparation of dicarbocyanine dyes.

What I claim as my invention and desire to be secured by Letters Patent of the United States is:

1. A polymethine dye intermediate selected from the group having the following general formula:

wherein It represents an organic radical selected from the group consisting of alkyl and aryl groups, R represents an alkyl group, x represents an acid radical, and Z represents the nonmetallic atoms necessary to complete a heterocyclic organic nucleus.

2. A polymethine dye intermediate selected from the group having the following general formula:

wherein R represents an organic radical selected from the group consisting of alkyl and aryl groups, R represents an alkyl group, x represents an acid radical, and Z represents the non-metallic atoms necessary to complete a heterocyclic.

wherein It represents an organic radical selected from the group consisting of alkyl and aryl groups, R represents an alkyl group and Z represents the non-metallic atoms necessary to complete a heterocyclic organic nucleus.

4. A polymethine dye intermediate selected from the group having the following general rormula:

wherein R represents an organic radical selected from the group consisting of alkyl and aryl groups, R represents an alkyl group, and Z represents thenon-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of quinoline, benzoxazole, benzothiazole, benzoselenazole, naphthoxazole, naphthothiazole and thiazoline nuclei.

5. A polymethine dye intermediate selected from the group having the following general formula:

wherein R and R each represent an alkyl group,

' X represents an acid radical and Z represents the non-metallic atoms necessary to complete a heterocyclic organic nucleus.

7. A polymethine dye intermediate selected from the group having the following general formula:

wherein R and R each represent an alkyl group, and Z represents the non-metallic atoms necessary to complete a heterocyclic organic nucleus.

8. A polymethine dye intermediate selected from the group having the following general formula:

wherein R and R each represent an alkyl group,

X represents an acid radical, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting oi quinoline, benzoxazole, benzothiazole, benzoselenazole, naphthoxazole, naphthothiazole and thiazoline nuclei.

9. A polymethine dye intermediate selected from the group having the following general formula:

wherein R and R each represent an alkyl group, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of benzoxazole, benzothiazole, benzoselenazole, naphthothiazole, naphthoxazole and thiazoline nuclei.

10. A polymethige dye intermediate selected from the group having the following general formula:

wherein R represents an alkyl group, and Z rep resents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of quinoline, benzoxazole, benzothiazole, benzoselenazole, naphthothiazole, naphthoxazole and thiazoline nuclei.

11. 2-(4-ethoxy- 1,3-butadienyl) -benzoxazole ethiodide.

15. In a process for preparing a polymethine' dye intermediate comprising condensing,"in-a-'re-, y action medium p-alkoxyacrolein acetal withu'a," cyclammonium quaternary salt containing" a methyl group in the alpha position, the step'whi'ch comprises employing, as reaction medium, glacial] acetic acid.

16. In a process for preparing a polyrnethine dye intermediate comprising condensing-ma re-"- action medium, a p-alkoxyacrolein acetalwith a cyclammonium quaternary iodide containing a methyl group in the alpha position, the step which comprises employing, as reaction-= medium, substantially anhydrous acetic acid.

17. In a process for preparing a-po methine' dye intermediate comprising condensing, :in a reaction medium, p-ethoxyacrolein dietliyl acetal with a cyclammonium quaternary salt'f'contaim, ing a methyl group in the alpha position, the step which comprises employing as-freaction;

medium, substantially anhydrous aceticiacid.

ROBERT H. sPfi AGuE.

medi m- 

